Documentation for sub model properties.

Resources/doc/reference/getting_started.rst

@@ -65,8 +65,11 @@ Step 3: Create Admin class
 
 Admin class represents mapping of your model and administration sections (forms,
 list, show). The easiest way to create an admin class for your model is to extend
-the Sonata\AdminBundle\Admin\Admin class. Here is a simple example from the
-SonataNewsBundle:
+the Sonata\AdminBundle\Admin\Admin class. For filter, list and show views, you can
+target a sub model property thanks to the dot-separated notation
+(eg: ``mySubModel.mySubSubModel.myProperty``).
+
+Here is a simple example from the SonataNewsBundle:
 
 .. code-block:: php